1. Field of the Invention
The present invention relates generally to the field of vehicular access systems, and more particularly to a wheelchair ramp with side barriers.
2. Description of the Related Art
Vehicular wheelchair access systems for handicapped persons, such as lifts and ramps, can be mounted on vehicles and deployable/stowable with respect to the vehicle. Wheelchair users typically must move their wheelchair along lift platforms and ramps in order to transfer from the ground to the vehicle and from the vehicle to the ground. Sidebarriers can be provided along the length of the ramp or lift platform as a safety precaution to prevent a wheelchair from moving or exiting over the sides of the ramp or platform outside the vehicle. Such sidebarriers may be affixed or deployable with the ramp. Examples of wheelchair ramps with side barriers are provided in U.S. Pat. No. 5,393,192 to Hall, et al. for “Underfloor Extendable Ramp for Vehicles” issued Feb. 28, 1995 and U.S. Pat No. 5,676,515 to Haustein for “Low Floor Vehicle Ramp” issued Jun. 3, 1996.
While the prior art recognizes the need for side barriers on wheelchair ramps, there remains room for additional improvements. The present invention is directed to satisfying these needs, among others. Whereas the prior art discloses side barriers fixedly-mounted or deployable with the ramp, several problems are associated with the prior art systems in that low-profiles may only be achieved with fixed barriers where the barrier height is of limited useful dimensions. On the other hand, spring-released barriers may be of limited use where the resilient spring actuation is susceptible to being defeated with obstacles or failure of the spring-actuated mechanism itself. Therefore, it would be desirable to provide a side-barrier actuator for use with the deployment of a substantial side barrier, which may not be defeated in the event that an obstacle holds down the barrier or in the event that the resilient spring member is rendered inoperable.